Simulation of Hydrogen Auto-Ignition in a Turbulent Co-flow of Heated Air with LES and CMC Approach

Stanković, Ivana; Triantafyllidis, A; Mastorakos, Epaminondas; Lacor, Christian; Merci, Bart

doi:10.1007/s10494-010-9277-0

Cited by 35 publications

(10 citation statements)

References 24 publications

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“…In the Cambridge experiment, CMC falls well within this inertial range, however, it is very difficult to ensure the same in the Berkeley and Calgary experiments where there is no estimation of neither integral or Kolmogorov length scales. In the present work, the selection of CMC has been driven by cost optimization, and resolutions are similar to previous LES-CMC calculations by various research groups [28,29,38,[50][51][52].…”

Section: Numerical Implementationmentioning

confidence: 99%

Flame Stabilization Mechanisms in Lifted Flames

Navarro‐Martinez

Kronenburg

2011

Flow Turbulence Combust

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Flame stabilization and the mechanisms that govern the dynamics at the flame base of lifted flames have been subject to numerous studies in recent years. A combined Large Eddy Simulation-Conditional Moment Closure (LES-CMC) approach has been successful in predicting flame ignition and stabilization by autoignition, but accurate modelling of the competition between turbulent quenching and laminar and turbulent flame propagation at the anchor point had not been demonstrated. This paper will consolidate LES-CMC results by analysing a wide range of lifted flame geometries with different prevailing stabilization mechanisms. The simulations allow a clear distinction of these mechanisms. It is corroborated that LES-CMC accurately predicts the competition between turbulence and chemistry during the auto-ignition process, the dynamics of turbulent flame propagation can be captured, however, the dynamics of the extinction process are not approximated well under certain conditions. The averaging process inherent in the CMC methods does not allow for an instant response of the transported conditionally averaged reactive species to the changes in the flow conditions and any response of the scalars will therefore be delayed. The dimensionality of the CMC implementation affects the solution and higher dimensionality does no necessarily improve results. Stationary or quasi-stationary conditions, however, can be well predicted for all flame configurations.

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Section: Numerical Implementationmentioning

confidence: 99%

Flame Stabilization Mechanisms in Lifted Flames

Navarro‐Martinez

Kronenburg

2011

Flow Turbulence Combust

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“…(6) as there are not clear advises what it should be, it turns out that depending on the flow problem it varies considerably. For instance, in the LES-CMC simulations of hydrogen autoignition [14,7] or methane bluff body stabilized flame [15] C N was assumed of the order of O(1) whereas in prediction of the local extinction [6] they assumed C N = 42 as the result of calibration for Sandia flame D. In the present paper it is demonstrated that C N may have a crucial influence on the flow field behavior.…”

Section: Model Formulation and Numerical Methods 21 Cmc For Liquid Fmentioning

confidence: 85%

LES/CMC of blow-off in a liquid fueled swirl burner

Tyliszczak

Mastorakos

2012

Proceeding of THMT-12. Proceedings of the Seventh International Symposium on Turbulence, Heat and Mass Transfer Palermo, Italy,

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Large Eddy Simulations of two-phase combustion with the Conditional Moment Closure sub-grid model have been performed for flow conditions corresponding to stable and blow-off regimes in a swirl heptane spray burner. In the case of stable flame (i.e. low velocity), the predicted location and shape of the flame agree well with high-speed camera images from an experiment. Using model constants previously calibrated against pilot jet flame with localised extinction, we obtain that at the experimentally determined blow-off velocity, the predicted flame also blows-off, demonstrating that the LES/CMC can capture global extinction of a realistic flame.

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“…The mechanism of Yetter et al [26], which is validated for CO and H 2 fuels over a wide range of temperature, was used previously by Navarro-Martinez and Jones [7] for LES of the case considered in this study. Stanković et al [6] compared different chemical mechanisms with respect to autoignition delays and used the Li mechanism [28] for LES. In that study, the ignition delays predicted by the Li mechanism and theÓ Conaire mechanism were found to be similar, but significant discrepancies with the Yetter mechanism were observed.…”

Section: Resultsmentioning

confidence: 99%

“…of presumed shape for the mixture fraction. Previously, this configuration was modelled with Conditional Moment Closure (CMC) by Mastorakos et al [5] and Stanković et al [6]. It is argued in [7] that amongst the presumed PDF methods, CMC is most adequate for predicting autoignition.…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of Autoignition in a Turbulent Hydrogen Jet Flame Using a Progress Variable Approach

Kulkarni

Polifke

2012

Journal of Combustion

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The potential of a progress variable formulation for predicting autoignition and subsequent kernel development in a nonpremixed jet flame is explored in the LES (Large Eddy Simulation) context. The chemistry is tabulated as a function of mixture fraction and a composite progress variable, which is defined as a combination of an intermediate and a product species. Transport equations are solved for mixture fraction and progress variable. The filtered mean source term for the progress variable is closed using a probability density function of presumed shape for the mixture fraction. Subgrid fluctuations of the progress variable conditioned on the mixture fraction are neglected. A diluted hydrogen jet issuing into a turbulent coflow of preheated air is chosen as a test case. The model predicts ignition lengths and subsequent kernel growth in good agreement with experiment without any adjustment of model parameters. The autoignition length predicted by the model depends noticeably on the chemical mechanism which the tabulated chemistry is based on. Compared to models using detailed chemistry, significant reduction in computational costs can be realized with the progress variable formulation.

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Simulation of Hydrogen Auto-Ignition in a Turbulent Co-flow of Heated Air with LES and CMC Approach

Cited by 35 publications

References 24 publications

Flame Stabilization Mechanisms in Lifted Flames

Flame Stabilization Mechanisms in Lifted Flames

LES/CMC of blow-off in a liquid fueled swirl burner

Large Eddy Simulation of Autoignition in a Turbulent Hydrogen Jet Flame Using a Progress Variable Approach

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